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Book Reviews theory' but he introduces a new method in the Book Reviews by Prof. W. J. Duncan, D.Sc, F.R.S. detailed solution of the problem of the load distri­ bution. The method depends on expanding an Reynolds number and of the fact that the sections Travaux du Laboratoire Aerodynamique. Vol. 1, expression, which in the usual British notation are not of types now used in practice, the data 1938. By E. Carafoli. (Imprimeria Nationala, will be of little interest to the aircraft industry. Bucarest. No price given.) would be written c/c si n θ, in a finite Fourier One minor point of terminology which appears Although this volume has only just come to hand it bears the date 1938 and it is, therefore, not to be worthy of comment is that profit a dièdre series in the cosines of 20 and its multiples; this surprising that most of the contents are con­ means a profile having a finite trailing edge angle, device is due to Irmgard Lotz, as the author siderably out of date. The book, which is written the idea being that there is a dihedral angle acknowledges. A number of detailed examples in French, begins by giving a general description between the tangent planes at the trailing show that wings of all common plan forms can be of the wind tunnel at the Ecole Polytechnique at edge. adequately represented by a few terms of this Bucarest. The general layout of the wind tunnel series. The novelty consists in obtaining the coef­ is very similar to that of the compressed air ficients in the expression for the lift distribution Théorie des Ailes Monoplanes D'Envergure Finie. tunnel at the N.P.L. but the tunnel works with by solving finite difference equations by the By E. Carafoli. (Imprimeria Nationala, Bu­ air at normal atmospheric pressure and the main Laplace integral. Some other topics discussed are carest. No price given.) structure is built of wood. The exterior casing of the lift distributions across the span in horizontal The author of this monograph, which is written the tunnel is in effect an independent building circling flight, continuous rotation about an axis in the French language, is a Professor at the exposed to the weather and takes the form of a parallel to the span, and the effects of deflected Ecole Polytechnique at Bucarest. He is well horizontal octagonal prism with truncated pyra­ ailerons. This publication will be of some interest known as an aerodynamicist on the Continent, midal ends. The working section is l·5 metres in to those who are concerned with the finer points particularly in France, and has collaborated with diameter and a driving motor of 40 kw. gives a of aerofoil theory, but 'lifting line theory' of the Professor Toussaint of the Sorbonne in aero­ top speed of 46 metres per second or very roughly monoplane is now somewhat vieuxjcu. It is to be nautical work. The monograph under review is 150 ft. per second. Results of tests on a consider­ hoped that the author will devote his undoubted entirely concerned with the 'Prandtl theory', or able variety of Joukowski aerofoils carried out at talents to 'lifting plane theory' and to problems what is now usually called the 'lifting line theory', a Reynolds number of a little below half-a-million of unsteady motion, where there are great of monoplane wings. The author avowedly bases are given in the report. On account of this low opportunities for research. his work on Glauert's treatment of 'lifting line sented has been made, but a few general con­ 4. Rotor blades should have a very 'clean' finish to keep down the power required for sustenta- clusions can be drawn: ROTOR PERFORMANCE tion and forward flight, and to make sure that 1. It is very desirable to allow the blades of a (Concluded from page 158) autorotation is easily maintained after engine rotor to flap about two axes lying in planes at measured and estimated characteristics compare. failure. right angles, to eliminate rolling moment on The value of CD used (found by trial and error 0 5. To avoid poor flow conditions over the blades the rotor as a whole and to eliminate fluctuat­ to give best agreement) was 0·012. The agreement in the retiring positions and to keep the rotor ing bending moments in the'individual blades. is good except for k at Values of a less than torque low, the highest rotational tip speed, T R The latter requires in addition a specific blade 8 deg. The 'hump' in the measured k curve does consistent with the avoidance of undesirable twist and curvature or weight distribution, and not occur in the case of the N.A.C.A. tests, and compressibility effects, should be used. But it is only possible to completely eliminate since the R. and M. tests showed appreciable from the point of view of power economy a fluctuating bending moments for one parti­ scale effect it is thought that the experimental low rotational tip speed is necessary, so cular condition of flight. curve shown may be abnormal at low values of that a compromise must be struck on this A possible alternative to the lift-flapping OR, where the mutual interference between the matter. motion would be a cyclic variation of pitch im­ blades is likely to be greatest. posed mechanically on the blades. There is no reason to doubt that the theory is Acknowledgment equally reliable when applied to helicopter con­ 2. It is necessary to provide mechanical damping The author is indebted to the Bristol Aeroplane ditions of operation. of the drag-flapping motion since there is very Co. Ltd. for permission to publish this paper, and little aerodynamic damping in this plane. wishes to acknowledge the assistance given by XIX. General Conclusions 3. A rotor with three or more blades is smoother Mr. J. N. B. Percy during the detailed develop­ No extensive application of the charts pre­ in operation than one with two blades. ment of the theory. Research Studies Directed. Toward the Development of PROFESSIONAL PUBLICATIONS Rational Vertical-Tail-Ioad Criteria. L. A. dousing Aerodynamic Centre and Centre of Pressure of an airfoil at Under this heading are given each month the principal articles of aeronautical interest appearing in the current Supersonic Speeds. H. W. Sibert issues of the journals of the leading Professional Societies and Institutions. Simple Analytical Equations for the Velocity of an Airplane in Unacceleratcd Level, Climbing and Diving Flight. H. B. The Royal Aeronautical Society Institute of the Aeronautical Sciences (U.S.A.) Freeman JOURNAL (Monthly) Wind-Tunnel Turbulence Effects. D. P. Riabouchinsky JOURNAL OF THE AERONA UTICAL SCIENCES (Monthly) Vol. 51, No. 436, April 1947 The Development of the Spitfire and Scafire. J. Smith Vol 14, No. 3, March 1947 AERONAUTICAL ENGINEERING REVIEW Development of Air Transport During the War. Air Marshal Sir Ralph Cochrane (Monthly) Investigations of 24 S-T Riveted Tension Joints. R. L. Feffcr- Mechanical Vibration and Acroclasticity. P. B. Walker man and H. L. Langhaar Vol. 6, No. 3, March 1947 Room Temperature Tensile Properties of Aluminium-Alloy The American Society of Mechanical Engineers Sheet following Brief Elevated Temperature Exposure. J. T. Civil Aviation—A New Economic Frontier. The Hon W. A. (U.S.A.) Lapsley, A. E. Flanigan, W. F. Harper and J. E. Dorn Harriman Some Ballistic Contributions to Aerodynamics. A. C. Charters The Army Air Forces Development Programme. Major-Gen. MECHANICAL ENGINEERING (Monthly) Beam-columns. W. R. Osgood L. C. Craigie Vol. 69, No. 4, April 1947 An Application of I.B.M. Machines to the Solution of the The Engineers' Part in the Civil Aviation Expansion Pro­ Flutter Determinant. E. L. Leppert, etc. gramme. The Hon W. A. M, Burden Recent Developments in Gas Turbines. A. Meyer STRESSES I N STREAMLINE SHELLS DU E T O Page 86, 3rd column, 22nd line: delete (12) ADIABATIC FLOW IN PIPES UNSYMMETRICA L LOADING Page 89: In order to correspond to the description To the Editor, given, the four photographs of Fig. 1 la should In the article under the above title by A. M. Binnie on pp. 125-6 of our last issue the blocks for be numbered, from top: (iii), (ii), (i) and (iv). DEAR SIR, Figs. 2 and 3 were made without notation and, The equation in the second line of the title of I should like to draw attention to the following unfortunately, the error was discovered too late Fig. 12 should read: misprints in my article on 'Adiabatic Flow in to be corrected. The correct drawings are given Pipes', which appeared in the February and 1/V7= -0·8+ 2 log (Re √f) below. March issues: Page 92, equation (A39.2) should read: p(1 +yM2)=const. Page 86, equation (11) should read: Yours faithfully, 21 Woodville Gardens, J. LUKASIEWICZ London, W.5 162 Aircraft Engineering http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

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Emerald Publishing
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Abstract

theory' but he introduces a new method in the Book Reviews by Prof. W. J. Duncan, D.Sc, F.R.S. detailed solution of the problem of the load distri­ bution. The method depends on expanding an Reynolds number and of the fact that the sections Travaux du Laboratoire Aerodynamique. Vol. 1, expression, which in the usual British notation are not of types now used in practice, the data 1938. By E. Carafoli. (Imprimeria Nationala, will be of little interest to the aircraft industry. Bucarest. No price given.) would be written c/c si n θ, in a finite Fourier One minor point of terminology which appears Although this volume has only just come to hand it bears the date 1938 and it is, therefore, not to be worthy of comment is that profit a dièdre series in the cosines of 20 and its multiples; this surprising that most of the contents are con­ means a profile having a finite trailing edge angle, device is due to Irmgard Lotz, as the author siderably out of date. The book, which is written the idea being that there is a dihedral angle acknowledges. A number of detailed examples in French, begins by giving a general description between the tangent planes at the trailing show that wings of all common plan forms can be of the wind tunnel at the Ecole Polytechnique at edge. adequately represented by a few terms of this Bucarest. The general layout of the wind tunnel series. The novelty consists in obtaining the coef­ is very similar to that of the compressed air ficients in the expression for the lift distribution Théorie des Ailes Monoplanes D'Envergure Finie. tunnel at the N.P.L. but the tunnel works with by solving finite difference equations by the By E. Carafoli. (Imprimeria Nationala, Bu­ air at normal atmospheric pressure and the main Laplace integral. Some other topics discussed are carest. No price given.) structure is built of wood. The exterior casing of the lift distributions across the span in horizontal The author of this monograph, which is written the tunnel is in effect an independent building circling flight, continuous rotation about an axis in the French language, is a Professor at the exposed to the weather and takes the form of a parallel to the span, and the effects of deflected Ecole Polytechnique at Bucarest. He is well horizontal octagonal prism with truncated pyra­ ailerons. This publication will be of some interest known as an aerodynamicist on the Continent, midal ends. The working section is l·5 metres in to those who are concerned with the finer points particularly in France, and has collaborated with diameter and a driving motor of 40 kw. gives a of aerofoil theory, but 'lifting line theory' of the Professor Toussaint of the Sorbonne in aero­ top speed of 46 metres per second or very roughly monoplane is now somewhat vieuxjcu. It is to be nautical work. The monograph under review is 150 ft. per second. Results of tests on a consider­ hoped that the author will devote his undoubted entirely concerned with the 'Prandtl theory', or able variety of Joukowski aerofoils carried out at talents to 'lifting plane theory' and to problems what is now usually called the 'lifting line theory', a Reynolds number of a little below half-a-million of unsteady motion, where there are great of monoplane wings. The author avowedly bases are given in the report. On account of this low opportunities for research. his work on Glauert's treatment of 'lifting line sented has been made, but a few general con­ 4. Rotor blades should have a very 'clean' finish to keep down the power required for sustenta- clusions can be drawn: ROTOR PERFORMANCE tion and forward flight, and to make sure that 1. It is very desirable to allow the blades of a (Concluded from page 158) autorotation is easily maintained after engine rotor to flap about two axes lying in planes at measured and estimated characteristics compare. failure. right angles, to eliminate rolling moment on The value of CD used (found by trial and error 0 5. To avoid poor flow conditions over the blades the rotor as a whole and to eliminate fluctuat­ to give best agreement) was 0·012. The agreement in the retiring positions and to keep the rotor ing bending moments in the'individual blades. is good except for k at Values of a less than torque low, the highest rotational tip speed, T R The latter requires in addition a specific blade 8 deg. The 'hump' in the measured k curve does consistent with the avoidance of undesirable twist and curvature or weight distribution, and not occur in the case of the N.A.C.A. tests, and compressibility effects, should be used. But it is only possible to completely eliminate since the R. and M. tests showed appreciable from the point of view of power economy a fluctuating bending moments for one parti­ scale effect it is thought that the experimental low rotational tip speed is necessary, so cular condition of flight. curve shown may be abnormal at low values of that a compromise must be struck on this A possible alternative to the lift-flapping OR, where the mutual interference between the matter. motion would be a cyclic variation of pitch im­ blades is likely to be greatest. posed mechanically on the blades. There is no reason to doubt that the theory is Acknowledgment equally reliable when applied to helicopter con­ 2. It is necessary to provide mechanical damping The author is indebted to the Bristol Aeroplane ditions of operation. of the drag-flapping motion since there is very Co. Ltd. for permission to publish this paper, and little aerodynamic damping in this plane. wishes to acknowledge the assistance given by XIX. General Conclusions 3. A rotor with three or more blades is smoother Mr. J. N. B. Percy during the detailed develop­ No extensive application of the charts pre­ in operation than one with two blades. ment of the theory. Research Studies Directed. Toward the Development of PROFESSIONAL PUBLICATIONS Rational Vertical-Tail-Ioad Criteria. L. A. dousing Aerodynamic Centre and Centre of Pressure of an airfoil at Under this heading are given each month the principal articles of aeronautical interest appearing in the current Supersonic Speeds. H. W. Sibert issues of the journals of the leading Professional Societies and Institutions. Simple Analytical Equations for the Velocity of an Airplane in Unacceleratcd Level, Climbing and Diving Flight. H. B. The Royal Aeronautical Society Institute of the Aeronautical Sciences (U.S.A.) Freeman JOURNAL (Monthly) Wind-Tunnel Turbulence Effects. D. P. Riabouchinsky JOURNAL OF THE AERONA UTICAL SCIENCES (Monthly) Vol. 51, No. 436, April 1947 The Development of the Spitfire and Scafire. J. Smith Vol 14, No. 3, March 1947 AERONAUTICAL ENGINEERING REVIEW Development of Air Transport During the War. Air Marshal Sir Ralph Cochrane (Monthly) Investigations of 24 S-T Riveted Tension Joints. R. L. Feffcr- Mechanical Vibration and Acroclasticity. P. B. Walker man and H. L. Langhaar Vol. 6, No. 3, March 1947 Room Temperature Tensile Properties of Aluminium-Alloy The American Society of Mechanical Engineers Sheet following Brief Elevated Temperature Exposure. J. T. Civil Aviation—A New Economic Frontier. The Hon W. A. (U.S.A.) Lapsley, A. E. Flanigan, W. F. Harper and J. E. Dorn Harriman Some Ballistic Contributions to Aerodynamics. A. C. Charters The Army Air Forces Development Programme. Major-Gen. MECHANICAL ENGINEERING (Monthly) Beam-columns. W. R. Osgood L. C. Craigie Vol. 69, No. 4, April 1947 An Application of I.B.M. Machines to the Solution of the The Engineers' Part in the Civil Aviation Expansion Pro­ Flutter Determinant. E. L. Leppert, etc. gramme. The Hon W. A. M, Burden Recent Developments in Gas Turbines. A. Meyer STRESSES I N STREAMLINE SHELLS DU E T O Page 86, 3rd column, 22nd line: delete (12) ADIABATIC FLOW IN PIPES UNSYMMETRICA L LOADING Page 89: In order to correspond to the description To the Editor, given, the four photographs of Fig. 1 la should In the article under the above title by A. M. Binnie on pp. 125-6 of our last issue the blocks for be numbered, from top: (iii), (ii), (i) and (iv). DEAR SIR, Figs. 2 and 3 were made without notation and, The equation in the second line of the title of I should like to draw attention to the following unfortunately, the error was discovered too late Fig. 12 should read: misprints in my article on 'Adiabatic Flow in to be corrected. The correct drawings are given Pipes', which appeared in the February and 1/V7= -0·8+ 2 log (Re √f) below. March issues: Page 92, equation (A39.2) should read: p(1 +yM2)=const. Page 86, equation (11) should read: Yours faithfully, 21 Woodville Gardens, J. LUKASIEWICZ London, W.5 162 Aircraft Engineering

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: May 1, 1947

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